Metabolic alterations induced by endotoxic shock and their mechanisms of control over the function of membrane-bound enzyme systems in relationship to changes in the membrane lipid profile will be investigated. The specific objectives include: (1) characterization of the metabolic alteration in the myocardial (Na ion plus K ion)-ATPase enzyme system and its correlation with the concomitant physical changes in lipid microenvironment during various stages of shock; (2) characterization of, and elucidation of mechanisms responsible for, changes in ouabain receptor dynamics during shock; (3) studies of the relationship between the turnover number of the (Na ion plus K ion)-APTase enzyme system and sodium pump activity following endotoxin administration; (4) analysis of the modification of the membrane lipid profile in shock; (5) investigation of phospholipid transfer between liposomes and myocytes; (6) correlation of shock-induced changes in phospholipase activities and those in the membrane lipid profile with mitochondrial adenine nucleotide translocase and carnitine palmitoyltransferase activities; and (7) studies of the shock-induced alteration of the isoenzyme pattern of pyruvate kinase in the heart. Information obtained from these studies will provide new insights into the pathophysiology of the myocardium during the development of shock.